We did not predict that A/A and A/C individuals would display higher HR after smoking marijuana than C/C individuals. Although individuals with a genetic predisposition to dependence on other drugs display heightened HR reactivity (Conrod et al. 1998), this result suggests that either the “risk” allele of the SNP is actually the A allele (as Sipe et al. 2002 and Flanagan et al. 2006 found), or that reduced HR reactivity to marijuana may be related to risk for CD.
